JPH0673209B2 - Magnetic recording / reproducing device - Google Patents

Description

The present invention relates to a rotary head type helical scan type magnetic recording / reproducing apparatus.

[Prior Art] In a magnetic recording / reproducing apparatus, a recording track on a magnetic tape is caused by a non-uniform head width or a variation in a head mounting position on a deck due to differences in manufacturers or models. In some cases, the locus of the rotary head at the time of actual reproduction does not coincide with the locus of the actual head. Therefore, it is necessary to perform tracking adjustment for tracing the locus of the rotary head at the time of reproduction to the recording track.

In the conventional magnetic recording / reproducing apparatus, the above tracking adjustment is performed using the reproducing FM envelope.

Specifically, while adjusting the position of the rotational head locus in the tape longitudinal direction during playback (hereinafter referred to as the adjustment of the tracking value), the maximum value of the playback FM envelope is detected and held, and the playback FM envelope is updated at any time. Compared with the maximum value stored while reading, the tracking value was adjusted automatically so that the maximum value of the constantly playing FM envelope could be obtained.

[Problems to be Solved by the Invention] As described above, the conventional magnetic recording / reproducing apparatus uses the maximum value of the reproduction FM envelope for the best tracking value. Is always subtle, and it is very difficult to accurately detect the maximum value of the playback FM envelope that fluctuates in this way. Therefore, hunting is likely to occur in tracking control and accurate operation is performed. There was a problem that I could not.

The present invention has been made to solve the above-mentioned problems, and it is possible to accurately detect the always-changing maximum value of the reproducing FM envelope, and perform highly accurate tracking adjustment operation without hunting or the like. It is an object to provide a magnetic recording / reproducing device.

[Means for solving problems]

A magnetic recording / reproducing apparatus according to the present invention controls the speed and phase of a drum motor for driving a rotary drum equipped with a rotary head and a capstan motor for running a magnetic tape, and controls pulses detected by a control head. In contrast to this, a tracking control servo system circuit that relatively automatically adjusts the tracking position of the rotary head in the longitudinal direction of the tape, and an envelope detector that detects an FM envelope proportional to the reproduced video signal reproduced from the rotary head during reproduction. A circuit, an A / D conversion circuit for A / D converting the FM envelope detection output from the envelope detection circuit and quantitatively ranking the tracking value of the rotary head and outputting the same, and a change in the tracking value Memorize the pattern of rank change of the playback FM envelope, A microcomputer that determines the maximum rank value of the reproduction FM envelope based on the stored pattern during reproduction and controls the tracking control servo system circuit so that a tracking value corresponding to the maximum rank value is obtained. Be prepared.

[Action]

According to the present invention, the FM envelope proportional to the reproduced video signal reproduced from the rotary head is detected, and the FM envelope detection output is quantitatively ranked with respect to the tracking value of the rotary head by the AD conversion circuit. Therefore, the pattern of the playback FM envelope's rank change with respect to the change in the tracking value is stored, so even if the playback FM envelope is constantly subtly fluctuated due to causes other than tracking, the integral action for the fluctuation is obtained. To be Then, at the time of playback, by the stored pattern,
The maximum rank value of the reproduction FM envelope is determined, and the tracking control servo system circuit is controlled so that the tracking value corresponding to the maximum rank value is obtained. In other words, even if the playback FM envelope is subject to fluctuations, the fluctuations can be divided into ranks with a certain width, so the maximum value of the playback FM envelope can be accurately captured, and the automatic tracking adjustment operation during playback can be performed easily and accurately. Can be done

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a servo system control circuit diagram in a magnetic recording / reproducing apparatus according to an embodiment of the present invention. In FIG. 1, (1) is a rotary drum, (2) and (3) are the rotary drums (1). It is a rotating head attached to the head, and the reproduction FM envelope is picked up while tracing the recording head locus recorded on the magnetic tape (7) by these heads (2) and (3). (13) is a head amplifier circuit, which amplifies the reproduced FM envelope with a constant gain. (14) is an envelope detection circuit, which detects the reproduced FM envelope and converts it into a DC voltage. (15)
Is an A-D conversion circuit, which converts the DC voltage into a digital signal and inputs the digital signal to the microcomputer (16).

Reference numeral (12) is a servo main IC circuit. The servo main IC circuit (12) passes through a capstan motor drive circuit (10) and a drum motor drive circuit (11), and then a capstan motor (9) and a drum motor. (4) The speed and phase of each are controlled, and at the same time, the microcomputer (16)
In response to a command from the control head (6), automatic adjustment of so-called tracking is performed to relatively adjust the positions of the rotating heads (2) and (3) in the tape longitudinal direction with respect to the control pulse picked up from the control head (6). . In FIG. 1, (5) is a drum PG head, and (8) is a capstan shaft.

Next, the operation of the above configuration will be described.

When the reproduction is started, the initial tracking value is designated from the microcomputer (16) to the servo main IC circuit (12). The value of the reproduced FM envelope at that time is input to the microcomputer (16) through the rotary heads (2) and (3), the head-up circuit (13), the envelope detection circuit (14) and the AD conversion circuit (15). At this time, the reproduced FM envelope is AD-quantized by the AD converter circuit (15) and quantized to quantitatively rank the tracking values, and A- The output of the D conversion circuit (15), that is, the pattern of the rank change of the reproduced FM envelope is stored.

Next, the microcomputer (16) causes the servo main IC circuit (12) to change from the initial tracking value to Δ
After the tracking value increased by t [ms] is designated and the servo system becomes stable, the reproduced FM envelope at this time is input to the microcomputer (16) and quantized and stored as described above.

The above operation is repeated according to the flow chart of FIG. 2 to store the pattern of the rank change of the reproduced FM envelope within a certain tracking range in the memory in the microcomputer (16).

That is, when the change in the magnitude of the envelope with respect to the change in the tracking value is as shown in FIG. 3, it is stored in the memory in the microcomputer (16) in the pattern as shown in FIG. Accordingly, the tracking value at the maximum value of the reproduction FM envelope can be calculated by (A + B) / 2, which is the average value of points A and B two ranks below the maximum envelope rank 14 in FIG. Finally,
By specifying a tracking value of (A + B) / 2 to the servo main IC circuit (12), it is possible to automatically adjust to the optimum tracking point where the reproduction FM envelope becomes maximum.

In the above embodiment, as shown in FIG. 4, the rank is 15 steps from 2 to 15, but the number of ranks may be any and the ranks may not be evenly spaced.

The number of ranks and the rank interval may be different between the standard mode and the long time mode.

When calculating the maximum value of the playback FM envelope, the points that are two ranks lower than the maximum rank are taken as the points A and B, respectively, but the average is taken, but it is not limited to 2 ranks, and the standard mode and long time It may be different depending on the mode.

Further, in FIG. 4, the tracking value is moved from D to E, but it is not necessary to store the envelope in such a wide range, and the tracking value is increased with the initial tracking value as the F point and the B point is found. A memory system in which the tracking value is reduced and the point A is found and the point C is reached may be set.

Furthermore, the storage operation of this pattern may be performed only once at the beginning of reproduction or may be performed constantly during reproduction.

As described above, according to the present invention, when the best tracking value is detected by using the maximum value of the reproduction FM envelope, the reproduction FM envelope is quantitatively ranked.
Since the pattern of rank change is stored and the maximum rank value is determined during playback, an integral action is obtained for the playback FM envelope that is constantly changing due to causes other than tracking, and the maximum playback FM envelope during playback is obtained. The value can be captured accurately. Therefore, it is possible to perform an extremely highly accurate tracking adjustment operation that is extremely strong against the reproduction FM envelope and does not cause hunting.

[Brief description of drawings]

FIG. 1 is a servo system control circuit diagram of a magnetic recording / reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a program flow chart, and FIG. 3 is a tracking value change and reproducing FM.
FIG. 4 is a graph showing changes in the envelope, and FIG. 4 is a graph in a state of being ranked. (1) ... Rotary drum, (2), (3) ... Rotary head, (4) ... Drum motor, (6) ... Control head, (7) ... Magnetic tape, (9) ... Cap Stun motor, (12) …… Servo system circuit for tracking control, (14) …… Envelope detection circuit, (15) …… A-
D conversion circuit, (16) ... Microcomputer. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. The speed and phase of a drum motor for driving a rotary drum having a rotary head mounted thereon and a capstan motor for running a magnetic tape are controlled, and the rotation is performed with respect to a control pulse detected by a control head. A tracking control servo system circuit that relatively automatically adjusts the tracking position of the head in the tape longitudinal direction, an envelope detection circuit that detects an FM envelope proportional to the reproduced video signal reproduced from the rotary head during reproduction, and this envelope A / D conversion circuit that A / D converts the FM envelope detection output from the detection circuit and quantitatively ranks and outputs the tracking value of the rotary head, and the rank of the reproduction FM envelope with respect to the change of the tracking value. Memorizes the pattern of change and stores it during playback. And a microcomputer for controlling the tracking control servo system circuit so as to obtain the tracking value corresponding to the maximum rank value of the reproduction FM envelope. And a magnetic recording and reproducing device.